> The thing is that if brushing your teeth means a world of pain then you do it out of obligation and it is not a happy experience.

Yes, investments often come in the form of obligations. Less than ten minutes each day is nevertheless cheap by self-care standards. Even by the standards of a person with pained teeth, they'd probably rather brush than undertake such a strict diet.

I'm aware that all of this must seem terribly condescending, so before I go on let me just say that I honestly have no issue with the solutions you've found to your problems -- even if I disagree with some of the logic that helped you arrive at them. Everything beyond this point will be my own attempts to straighten established facts from the rest for the benefit of other readers. Live well and go in peace, friend.

> If brushing your teeth means a world of pain then you do it out of obligation and it is not a happy experience

If gentle, careful brushing causes a world of pain... that is not normal and indeed a strong indicator of advanced oral disease. Once disease advances beyond a certain point, the only reliable solution becomes professional dental treatment.

> My point still stands though, there is a lot of money made from tooth related FUD and sugary food. I just wished a dentist had spilled the beans to me many decades ago that it really is simple to have excellent oral hygiene just be avoiding the added sugars, and, to a lesser extent, the processed food.

The vast majority of dentists do want people to be healthy. It's just human nature. The core issue is that most patients don't want to be lectured -- it's bad for repeat business, so dentists learn to stay quiet about such things unless asked. Yet another one of the many tragedies caused by the systemic monetization of healthcare and something which I think we should all be more insistent about fixing.

> By every metric I just find the situation very different, the gums have definitely 'grown back' and I am sure some tartar is now below the gumline.

That is most excellent and I am genuinely pleased to hear that you are in good health. It's important to note for others, however, that the capacity for gums to "grow back" in most cases is usually lackluster. The best way to fix receding gums is to prevent the recession before it occurs with regular care -- the next best thing to do is brush and floss (or water floss!) diligently, receive regular cleanings, and maintain the routine consistently for the rest of your life.

> Many common preservatives kill bacteria, or specific bacteria such as 'anything but yeast'. This makes sense for shelf life but I am not sure it helps with the gastrointestinal tract, which includes the mouth. There are good bacteria and then there is the one that lives off sucrose to make plaque. If you are eating standard issue bakery products then you are killing off the bad guys whilst giving the yeast=like strains that live off sucrose a free pass.

This is an incredible oversimplification. Salt -- for example -- is itself a powerful preservative and you certainly would kill most gut bacteria by ingesting a sufficiently large dose... though such a large dose would prove equally deadly to the host. Preservatives are not antibiotics, they work because they're concentrated in the food and get quickly rendered harmless once eaten thanks to diffusion (Yes, even in the mouth. You can thank your saliva.)

You are of course still correct to say that modern diets wreak havoc on gut fauna, but the cause is rooted in nutrition rather than poisoning. Fauna which are beneficial in a diverse gut can turn toxic in an environment with lower biodiversity -- something which is all too easy to cause with an unbalanced diet that systematically favors only a fraction of the extant species. Sugar-heavy diets are but one of many problematic cases in this respect.

> Incidentally, after I banished sugar from my home, I was reading the label of the toothpaste one day whilst brushing my teeth. And you will never guess what? Sugar. The cheek of it, putting sugar in toothpaste. That is perpetuating a problem that was being set out to be solved.

That's sad to hear and I'm sorry you've been failed like this. With that being said... I suspect that the incentives at play are not what you imply. The toothpaste manufacturer really has very little interest in the profits derived by whichever odd dentist happens to work on your teeth -- they probably just needed a cheap filler that didn't taste bad. None of this diminishes the evil caused by such greed, but we need to be clear-eyed about where the fault lies if we want to make things better.

> I cut coffee and dairy too, so it is not difficult or a challenge to put in the effort to get them really nice for when I am meeting someone. However, I no longer feel obligated to brush them twice a day lest they feel like they are falling out or 'covered in fur' the next morning.

I want to stress again to anyone reading this that brushing is the singlemost effective way to delay the development of calculus and thus prevent tooth decay. Even if you can't feel the plaque, it's still there and almost certainly forming new calculus.

As a side-note: you may be interested to hear that plain coffee is not particularly bad for your teeth. One should avoid drinking it before brushing because the acidity can temporarily soften enamel, but aside from that all you'd have to worry about are coffee stains. Tea is similarly safe and even has a gentler PH, making most brews safe to drink even before brushing.

> It is not rocket science but I did not feel that any of this was explained to me very clearly at school or on any TV science program

I agree. Knowledge of such things is woefully undertaught. Schools seem much too eager to abdicate the responsibility for such things to parents who themselves may have never been fully taught. It is for this reason that we must often rely on the expertise of other professionals to make up for our own shortcomings, even as we simultaneously seek knowledge on our own terms.